Field
Implementations described herein generally relate to semiconductor manufacturing and more particularly to temperature controlled substrate support assembly and method of using the same.
Description of the Related Art
As the feature size of the device patterns get smaller, the critical dimension (CD) requirement of features becomes a more important criterion for stable and repeatable device performance. Allowable CD variation across a substrate processed within a processing chamber is difficult to achieve with due to chamber asymmetries such as chamber and substrate temperature, flow conductance, and RF fields.
In processes utilizing an electrostatic chuck disposed on a cooling base to secure the substrate during processing, uniform temperature control across the surface of the substrate is even more challenging due to the non-homogeneous construction of the chuck below the substrate. For example, some regions of the electrostatic chuck have gas holes, while other regions have lift pin holes that are laterally offset from the gas holes. Still other regions have chucking electrodes, while other regions have heater electrodes that are laterally offset from the chucking electrodes. Since the structure of the electrostatic chuck can vary both laterally and azimuthally, uniformity of heat transfer between the chuck and substrate is very difficult to obtain, resulting in local hot and cold spots across the chuck surface, which consequently results in non-uniformity of processing results on the substrate.
The lateral and azimuthal uniformity of heat transfer between the chuck and substrate laterally is further complicated by heat transfer schemes commonly utilized in conventional cooling bases to which the electrostatic chuck is mounted. For example, conventional cooling bases typically have only edge to center temperature control. Thus, local hot and cold spots within the electrostatic chuck cannot be compensated for utilizing the heat transfer features of conventional cooling bases.
Thus, there is a need for an improved substrate support assembly.